NL1019753C2 - Technique for forming expandable devices from cells that can be transferred between a contracted position and an expanded position. - Google Patents

Description

Technique for Forming Expandable Devices from Cells That Can Be Transferred Between a Collapsed Position and an Expanded Position The following is based on and claims the priority of Provisional Application No. 60 / 261,749 filed January 16, 2001 and June 8, 2001 Provisional Application No. 60 / 296,875 filed.

This invention relates generally to expandable devices and in particular to devices formed from one or more expandable cells that facilitate transition of the device from a contracted position to an expanded position.

In a number of applications and environments, it will be advantageous to have a device suitable for transition from a contracted position to an expanded position. Such devices may be provided with flat parts, tubular parts, rectangular parts and with a number of other shapes. Examples of applications include medical applications in which expandable devices, such as stents, are positioned at a desired location and then expanded. Another example of an application involves the use of expandable members in the recovery of different fluids, for example oil, from underground locations.

For example, fluids such as oil, natural gas, and water are obtained from underground geological formations (a "reservoir") by drilling a well that permeates the fluid-bearing formation. Once a well bore has been drilled to a certain depth, the wall of the borehole is usually supported to prevent collapse. During the drilling and use of a well bore, various tubular members such as liners, jackets, sand screens, etc. are arranged within the well bore.

Various methods have been developed for radially expanding tubular members, for example by pulling an expansion mandrel through the tubular member to plastically deform the tubular member in a radial outward direction. However, such an approach requires a large amount of force to achieve the desired expansion.

The medical industry, oil industry and a number of other industries use certain types of expandable organs or will benefit from the use of expandable organs in many applications. However, there are few existing devices that are easy to expand at a desired location. With the devices that exist, considerable forces are required to effect the expansion. Also, considerable plastic deformation often occurs, which can limit the choice of available materials for a given expandable device.

The present invention is directed to overcoming or at least reducing the effects of one or more of the problems outlined above.

The present invention generally relates to expandable devices that can be used, for example, in underground environments. In an embodiment of the invention, the expandable device comprises one or more expandable cells that facilitate expansion of the device. For example, a tubular member may be formed with a plurality of expandable cells that facilitate radial expansion of the device from a collapsed or contracted position to an expanded position. A number of cell types and cell designs can be used depending on the application and desired parameters of the expandable device.

The invention will be described below with reference to the accompanying drawings in which the same reference numerals designate corresponding elements, and: figures 1A and 1B are illustrations of the forces prescribed for the manufacture of a bi-stable structure; Figures 2A and 2B show force-deflection curves of two bi-stable structures; Figures 3A-3F show expanded and collapsed positions of three bi-stable cells with different thickness ratios; Figures 4A and 4B show a bi-stable expandable tubular member in its expanded and collapsed positions; Figures 4C and 4D show a bi-stable expandable tubular member in collapsed and expanded positions within a well bore; Figures 5A and 5B show an expandable deployment device of packing type; Figures 6A and 6B show an insertion device of a mechanical packing type; Figures 7A-7D show an expandable forge-type device; Figures 8A-8D show a piston-type insertion device; Figures 9A and 9B show a plug-type insertion device; Figures 10A and 10B show a ball-type insertion device; Figure 11 is a diagram of a wellbore using an expandable bi-stable tubular member; Figure 12 shows a motor-driven insertion device with radial rollers; Figure 13 shows a hydraulically driven device with radial rollers; Figure 14 is a cross-sectional view of an embodiment of the gasket of the present invention; Figure 15 is a cross-sectional view of another embodiment of the gasket of the present invention; Figure 16 is a side view of an embodiment of the present invention in a contracted position; Figure 17 is a side view of an embodiment of the present invention in an expanded position; 1019753 4 Figures 18A-C are schematic views of an alternative embodiment of the present invention; Figure 19 is a perspective view of an alternative embodiment of the present invention; Figure 20 is a schematic view of an alternative embodiment of the present invention; Figure 21 is a schematic view of an alternative embodiment of the present invention; Figures 22A-B are a partial side view of an embodiment of the present invention in the contracted and expanded positions; Figures 23A-B are partial side views of an embodiment of the present invention in the contracted and expanded positions; Figures 24A-B are side views of an alternative embodiment of an expandable cell in its contracted or expanded position; Figures 25A-B are side views of a cell similar to that shown in Figures 24A-B deployed in its contracted and expanded positions, respectively; Figures 26A-B show another embodiment of an expandable cell, respectively shown in its contracted and expanded position; Figures 27A-B show another embodiment of expandable cells, depicted in their contracted and expanded positions, respectively; Figures 28A-B show another embodiment of expandable cells, respectively, depicted in their contracted and expanded positions; Figures 29A-B show another embodiment of expandable cells, respectively, depicted in their contracted and expanded positions; Figures 30A-B show another embodiment of an expandable cell, respectively shown in its contracted and expanded position; Figures 31A-C show a cell with energy storage means moving from a contracted position to an expanded position; Figures 32A-B show another embodiment of the cell shown in Figures 31A-C in a contracted position and expanded position, respectively; Figure 33 shows another example of an expandable cell design; Figure 34 shows another example of an expandable cell design; 35A-D shows an example of a locking mechanism 15, moving through different phases from a closed position to an open locked position; Figures 36A-D show another embodiment of the locking mechanism of Figure 35; Figure 37 shows a locking mechanism combined with an expandable cell; Figures 38A-B show an expandable cell combined with a locking mechanism in a collapsed or expanded position; Figure 39 shows an expandable cell with another embodiment of a locking mechanism; Figures 40A-B show a separate expandable cell or a number of expandable cells, combined with corresponding locking mechanisms; Figures 41A-B show another embodiment of combined expandable cells and locking mechanisms in collapsed and expanded positions; and Figure 42 is a schematic representation of the combination of expandable cells of different sizes and configurations in a single expandable device.

Although the invention is susceptible to various modifications and alternative forms, specific embodiments are shown there by way of example in the drawings and are described herein in detail. It is to be understood, however, that herein the description of specific embodiments is not intended to limit the invention to the particular form disclosed, but rather, it is intended to cover all modifications, equivalents, and alternatives that fall within the spirit and scope of the invention as defined. by the appended claims.

The following describes a number of expandable devices that use expandable cells to facilitate expansion of the device from a contracted position to an expanded position. Various expansion techniques, expandable cell designs, and locking mechanisms are described, and usually the description relates to one or more exemplary applications. The cells are described, for example, for use in tubular members, such as tubular members used in the oil production industry. However, this application is only an example of an application to demonstrate the applicability of the various cells and locking mechanisms described herein. The description is not to be construed as limiting the use of such expandable devices to the particular environments or applications described herein. Much earlier, the techniques for formulating expandable devices can have a wide range of applications in other environments and industries.

As described below, exemplary expandable devices may include bi-stable cells or not. Whether or not stable, the expandable cells facilitate expansion of a given device between a contracted position and an expanded position for a number of operations or procedures. The choice of a certain type of expandable cell depends on a number of factors including environment, degree of expansion, available materials, etc.

Bi-stable devices used in the present invention can take advantage of a principle shown in Figures 1A and 1B.

Figure 1A shows a rod 10 attached to rigid supports 12 at each end. If the rod 10 is subjected to an axial force, it begins to deform as shown in Figure 1B. If the axial force is increased, the rod 10 finally reaches its Euler buckling limit and deflects to one of the two stable positions shown as 14 and 15. If the buckled rod is now clamped in the buckled position, a force perpendicular to the longitudinal axis can cause the rod to move to one of the stable positions but not to another position. If the rod is subjected to a lateral force, it must move through an angle β for deflection to its new stable position.

Bi-stable systems are characterized by a force-deflection curve such as that shown in Figures 2A and 2B. The force 16 applied externally causes the rod 10 of Figure 1B to move in the direction X and reaches a maximum of 18 at the start of shifting from one stable configuration to the other. Further deflection requires less force because the system now has a negative spring value and if the force becomes zero, the deflection to the second stable position is spontaneous.

The force deflection curve for this example is symmetrical and is shown in Figure 2A. By introducing either a pre-curvature on the rod or an asymmetrical cross section, the force deflection curve can be made asymmetrical as shown in Figure 2B. In this system, the force 19 required to cause the rod to assume a stable position is greater than the force 20 required to cause the reverse deflection. The force 20 must be greater than zero for the system to have bi-stable characteristics.

Bi-stable structures, sometimes referred to as tumbling devices, have been used in the industry for such devices as flexible disks, dead-end clamps, hold-down devices, and quick-release systems for tension cables (such as in pardon-locking of sailing boats).

Instead of using the rigid supports as shown in Figs. 1A and 1B, a cell can be manufactured in which the restriction is provided by curved struts connected at each end as shown in Figs. 3A-3F. If both struts 21 and 22 have the same thickness as shown in Figures 3A and 3B, the force deflection curve is linear and the cell, when compressed from its open position, Figure 3B to its closed position, Figure 3A. If the cell shores have different thicknesses, as shown in Figures 3C-3F, the cell has a power deflection characteristic shown in Figure 2 and does not change in length if it moves between its two stable positions. An expandable bi-stable tubular member can thus be designed such that when the radial dimension expands, the axial length 20 remains constant. In one example, if the thickness ratio is above about 2: 1, the heavier brace withstands changes in length. The opening and closing force can be changed by changing the ratio of thick-to-thin brace dimensions. Figures 3C and 3D, for example, show a thickness ratio of approximately 3: 1, and Figures 3E and 3F show a thickness ratio of approximately 6: 1.

A bi-stable tubular member with an expandable drill, such as a casing, a tube, a piece, or pipe, can be fabricated with a plurality of circumferentially bi-stable connected cells 23, as shown in Figs. 4A and 4B in which each thin strut 21 is connected to a thick strut 22. The longitudinal flexibility of such a tubular member can be changed by changing the length of the cells and by connecting each row of cells with a compliant link. The force deflection characteristics and the longitudinal flexibility can also be further changed by the design of the cell shape. Figure 4A shows an expandable bi-stable tubular member 24 in its expanded shape, while Figure 4B shows the expandable bi-stable tubular member in its contracted or collapsed position. Within this application, the term "collapsed" is used to identify the shape of the bi-stable element or device in the stable position with the smallest diameter, whereby it is not intended to indicate that the element or device is damaged in any way is.

In the collapsed position, bi-stable tubular member 24 is easily inserted into a well bore 29, as shown in Figure 4C. After placement of the bi-stable tubular member 24 at a desired wellbore location, it is expanded as shown in Figure 4D.

The geometry of the bi-stable cells is such that the tubular cross section can be expanded in the radial direction to increase the overall diameter of the tubular member. As the tubular member expands radially, the bi-stable cells deform elastically until a specific geometry is achieved. At this point the bi-stable cells move, for example, to a final expanded geometry. With some materials and / or bi-stable cell designs, enough energy can be released in the elastic deformation of the cell (if every bi-stable cell passes beyond the specific geometry) for the expanding cells to be able to initiate the expansion of neighboring bi-stable cells beyond the critical bi-stable cell geometry. Depending on the deflection curves, a portion or even an entire length of bi-stable expandable tubular member can be expanded from a single point.

If radial compressive forces are exerted on an expandable bi-stable tubular member, it contracts radially in a similar manner and elastically deforms the bi-stable cells until a critical geometry is achieved. At this point the bi-stable cells snap to a ultimately collapsed structure. In this way the expansion of the bi-stable tubular member is reversible and repeatable. The bi-stable tubular member can therefore be a reusable tool that is selectively switched between the expanded position as shown in Figure 4A and the collapsed position as shown in Figure 4B.

In the collapsed position as in Figure 4B, the bi-stable expandable tubular member is easily inserted into the well bore and placed in position. A deployment device is then used to change the configuration from the collapsed position to the expanded position.

In the expanded position, as in Figure 4A, design control of the elastic material properties of each bi-stable cell can be such that a constant radial force can be applied through the tubular wall to the enclosed surface of the well bore. The material properties and the geometric shape of the bi-stable cells can be designed to give certain desired results.

An example of designing for certain desired results is an expandable bi-stable tubular strand with more than a diameter along the length of the strand. This may be useful in boreholes with varying diameters, either designed in this way or as a result of unplanned events, such as leaching of formation or clamp seats within the borehole. This may also be beneficial if it is desired to have a portion of the bi-stable expandable device disposed within a jacketed section of the well, while another portion is disposed in a non-jacketed portion of the well. well.

1019753 11

Figure 11 shows an example of this state. A well bore 40 is drilled from the surface 42 and includes a cased portion 44 and an open hole portion 46. An expandable bi-stable device 48 which has segments 50, 52 with 5 different diameters is placed in the well. The segment with a larger diameter 50 is used to stabilize the portion 46 in the form of an open hole of the well, while the segment with a reduced diameter 52 is arranged within the jacketed portion 44 of the well.

Bi-stable collars or connectors 24A (see Figure 4C) may be designed to allow portions of the bi-stable expandable tubular member to be joined together in a strand of useful lengths using the same principle as shown in Figures 4A and 4B. This bi-stable connector 24A also includes a bi-stable cell design that allows it to radially expand using the same mechanism as the bi-stable expandable tubular component. Exemplary bi-stable connectors have a diameter a little larger than the expandable tubular sections to be connected. The bi-stable connector is then placed over the ends of the two sections and mechanically attached to the expandable tubular sections. Mechanical fasteners, such as screws, nails, or bands, can be used to connect the connector to the tubular sections. The bi-stable connector is conventionally designed to have an expansion value that is compatible with the expandable tubular sections so that it continues to connect the two sections after the expansion of the two segments and the connector.

Alternatively, the bi-stable connector may have a diameter smaller than the two connected expandable tubular sections. The connecting member is then inserted into the interior of the ends 1019753 12 of the tubular members and mechanically attached as discussed above. Another embodiment will include machining the ends of the tubular sections on either their inner or outer surface to form an annular recess 5 in which the connector is disposed. A connector designed to fit into the recess is placed in the recess. The connecting member will then be mechanically attached to the ends as described above. In this way the connecting member forms a relatively flat connection with the tubular sections.

A conveyor device 31 transports the bi-stable expandable tubular lengths and bi-stable connectors in the well bore and to the correct position (see Figures 4C and 4D). The transport device can use one or more mechanisms, such as telegraph line cable, wound tube, wound tube with telephone conductor, drill pipe, tube or jacket.

A seating device 33 may be included in the overall assembly to expand the bi-stable expandable tubular members and connectors (see Figures 4C and 4D).

Insertion devices can be of numerous types, such as an inflatable packing element, a mechanical packing element, an expandable forging member, a piston device, a mechanical operating member, an electric solenoid, a plug-type device, for example a conically shaped device which is pulled through the tube or pushed, a ball-type device or a swivel-type expansion member, as further discussed below.

An inflatable packing element is shown in Figures 5A and 5B and is a device with an inflatable bladder, element, or bellows, which is included in the bistable expandable tubular system of the assembly to be used in the bottom of the borehole. In the representation of Figure 5A, the inflatable gasket element 25 is disposed within the entire length or part of the bi-stable tubular member 44 in the collapsed position and all bi-stable expandable connecting members (not shown). Once the bi-stable expandable tubular system is at the correct insertion depth, the inflatable packing element 25 is radially expanded by pumping fluid into the device, as shown in Figure 5B. The inflation fluid can be pumped from the surface through tube, or drill pipe, a mechanical pump, or via an electric pump located below the borehole, which is powered by a telephone cable.

When the inflatable packing element 25 expands it forces the bi-stable expandable tubular member 24 to also expand radially. At a certain expansion diameter, the inflatable packing element causes the bi-stable cells in the tubular member to reach a critical geometry in which the bi-stable "snap" effect is initiated and the bi-stable expandable tubular system expands to its final diameter. Finally, the inflatable packing element 25 is drained and removed from the deployed bi-stable expandable tubular member 24.

A mechanical packing element is shown in Figures 6A 20 and 6B and is a device with a deformable plastic element 26 that expands radially when compressed in the axial direction. The force to compress the element can be supplied by a compression mechanism 27, such as a screw mechanism, cam, or a hydraulic piston. The mechanical packing element inserts the bi-stable expandable tubular members and connecting members in the same manner as the inflatable packing member. The deformable plastic element 26 applies an outwardly directed radial force to the inner circumference of the bi-stable expandable tubular members and connecting members allowing them in turn to expand from a contracted position (see Figure 6A) to a final insert diameter ( see figure 6B).

1 0 1 9753 14

An expandable forging member is shown in Figures 7A-7D and includes a plurality of fingers 28 arranged radially about a conical mandrel 30. Figures 7A and 7C show side and top views, respectively. If the mandrel 30 is pulled or pushed by the fingers 28, they expand radially outwards, as shown in Figures 7B and 7D. An expandable forging member is used in the same way as a mechanical packing element for inserting a bi-stable expandable tubular member and connector.

A piston-type device is shown in Figures 8A-8D and includes a number of radially outwardly directed pistons 32 which are used as a mechanism for expanding the bistable expandable tubular members and connectors. When energized, the pistons 32 apply a radially directed force to deploy the bi-stable expandable tubular assembly such as the inflatable gasket element. Figures 8A and 8C show the pistons withdrawn, while Figures 8B and 8D show the pistons extended. The piston type device can be operated hydraulically, mechanically or electrically.

A plug-type actuator is shown in FIGS. 9A and 9B and includes a plug 34 which is pulled or pushed by the bi-stable expandable tubular members 24 or connecting members, as shown in FIG. 9A. The plug is sized to expand the bi-stable cells beyond their critical point where they will snap to a final expanded diameter as shown in Figure 9B.

A ball-type actuator is shown in Figures 10A and 10B and operates if an excess of ball 36 is pumped through the center of the bistable expandable tubular members 24 and connecting members. To prevent fluid losses through the cell slots, an expandable elastomer-based liner 38 is passed within the bi-stable expandable tubular system. The liner 38 acts as a seal and allows the ball 36 to be hydraulically pumped through the bi-stable tubular member 24 and connecting members. The effect of pumping the ball 36 through the bi-stable expandable tubular members 24 and connectors is to expand the cell geometry beyond the critical bi-stable point while allowing full expansion to occur as shown in Figure 10B. Once the bi-stable expandable tubular members and connectors are expanded, the elastomeric sleeve 38 and ball 36 are retracted.

Radial roller type actuators can also be used to expand the bi-stable tubular sections. Figure 12 shows a motor-driven expandable tool with radial rollers. The tool comprises one or more sets of arms 58 that are expanded to a certain diameter by means of a mechanism 15 and pivoting. At the end of each set of arms is a roll 60.

Centralizing members 62 may be attached to the tool to position it precisely within the well bore and the bi-stable tubular member 24. A motor 64 provides the power to rotate the entire assembly thus rotating the roller (s) in circumferential direction within the well bore. The axis of the roller (s) is such as to enable the roller (s) to rotate freely when brought into contact with the inner surface for the tubular member. Each roll can be conically shaped in section to increase the contact area of roll surface on the inner wall of the tubular member. The rollers are initially retracted and the tool is fed into the collapsed bi-stable tubular member. The tool is then rotated by the motor 64 and rollers 60 are moved outward to contact the interior surface of the bi-stable tubular member. Once in contact with the tubular member, the rollers are pivoted outwardly over a greater distance for applying an outwardly directed radial force to the bi-stable tubular member. The outward movement of the rollers can be effected via centrifugal force or a suitable operating mechanism coupled between the motor 64 and the rollers.

The final pivot position is set at a point 5 at which the bi-stable tubular member can be expanded to the final diameter. The tool is then moved longitudinally through the collapsed bi-stable tubular member while the motor continues to rotate pivot arms and rollers. The rollers follow a shallow helical path 66 within the bi-stable tubular member 10 while expanding the bi-stable cells in their path. Once the bi-stable tubular member has been deployed, tool rotation is stopped and the rollers are retracted. The tool is then withdrawn from the bi-stable tubular member by a transport device 68, which can also be used to insert the tool.

Figure 13 shows a hydraulically driven insertion device with radial rollers. The tool comprises one or more rollers 60 which are brought into contact with the inner surface of the bi-stable tubular member with the aid of a hydraulic piston 70. The outwardly directed radial force applied by the rollers can be increased to a point where the bi-stable tubular member expands to its final diameter. Centralizing members 62 may be attached to the tool to be positioned precisely within the well bore and bi-stable tubular member 44. The rollers 60 are initially withdrawn and the tool is fed into the collapsed bi-stable tubular member 24. The rollers 60 are then deployed and pressed against the inner wall of the bi-stable tubular member 24 to expand a portion of the tubular member to its final diameter. The entire tool is then pushed or pulled longitudinally through the bi-stable tubular member 24 while expanding the entire length of bi-stable cells 1019753 17 23. Once the bi-stable tubular member 24 has been deployed in its expanded position the rollers 60 are retracted and the tool is withdrawn from the well bore by the transport device 68 used for insertion thereof. By changing the axis of the rollers 60 the tool can be rotated via a motor if it is longitudinally driven by the bi-stable tubular member 24 moves.

Power for actuating the deployment device can be extracted from one or a combination of sources, such as electrical power supplied either from the surface or stored in a battery arrangement at the deployment device, hydraulic power supplied by pumps on the surface or at the bottom of the hole, turbines or a fluid accumulator, and mechanical power supplied through a suitable coupling, actuated by surface-mounted movement or stored at the bottom of the borehole, such as in a spring mechanism.

The bi-stable expandable tubular system is designed such that internal diameter of the deployed tubular member is expanded to maintain maximum cross-sectional area along the expandable tubular member. This feature allows mono-boreholes to be manufactured and facilitates elimination of problems associated with conventional wellbore casing systems in which the outer diameter of the casing in long wellbore must be reduced many times while limiting access.

The bi-stable expandable tubular system can be used in numerous applications such as an expandable open hole liner 25 where the bi-stable expandable tubular member 24 is used to support an open hole formation by exerting an external radial force on the surface of the well bore. Since bi-stable tubular member 24 is expanded radially, the tubular member moves into contact with the surface forming the well bore 29. These radial forces help stabilize the formation and allow the drilling of wells with less common mantle strands. The open hole 1019753 18 can also be provided with a material, for example, a covering that reduces the amount of fluid loss from the well bore in the formations. The covering can be made from a number of materials, including expandable metallic and / or elastomeric materials.

Reducing fluid loss in the formations can reduce the spending on drilling fluids and minimize the loss of circulation and / or borehole.

Liners can also be used within tubular well bore members for purposes such as corrosion protection. An example of a corrosive environment is the environment that results if carbon dioxide is used to promote oil extraction from a production formation. Carbon dioxide (CO 2) reacts easily with any water (H 2 O) present to form carbonic acid (H 2 CO 3). Other acids can also be generated, in particular if sulfur compositions are present. Tubular members used for injecting the carbon dioxide as well as those used in the manufacture of wells are subject to greatly increased corrosion values. The present invention can be used to place protective liners, for example, a bi-stable tubular member 24 within an existing tubular member, to minimize corrosion effects and increase the useful life of the wellbore tubes.

An exemplary application involves use of bi-stable tubular members 24 as an expandable perforated liner. The open bi-stable sets in the bi-stable expandable tubular member allow unlimited flow from out of the formation to provide a borehole stabilization structure.

Yet another application of the bi-stable tubular member 24 is as an expandable sand screen where the bi-stable cells are sized to act as a sand control screen. A fi lter material can also be combined with a bistable tubular member, as explained above. For example, an expandable shield element may be attached to the bi-stable expandable tubular member. The expandable shielding element may be formed as a casing around bi-stable tubular member 24. It has been found that the application of hoop tension forces to the wall of a borehole will in itself help to stabilize formation and reduce or reduce the influx of sand from production areas. to eliminate even if no additional screen element is used.

The above-described bi-stable expandable tubular members can be manufactured in a number of ways, such as: cutting off appropriately shaped webs through the wall of a tubular pipe thereby creating an expandable bi-stable device in its collapsed position; cutting patterns in a tubular pipe thereby creating an expandable bi-stable device in its expanded position and then compressing the device in a collapsed position; cutting suitable webs through a material plate, rolling the material into a tubular shape and joining the ends to form an expandable bi-stable device in its collapsed position; or cutting patterns in a material plate, rolling the material into a tubular shape, connecting the adjacent ends to form an expandable bi-stable device in its expanded position and then compressing the device in its collapsed position.

The structural material and the bistable expandable tubular members may include those commonly used in the oil and gas industry, such as carbon steel. They can also be made from special alloys (such as monel, inconel, hastelloy or tungsten-based alloys) if the application requires it.

The illustrated configurations for the bi-stable tubular members 24 are illustrative of the operation of a bi-stable base cell. Other designs may be suitable, but the displayed concept is also valid for these other geometries.

1019753 20

Figures 14 and 15 show a gasket 80 made of bi-stable cells. The gasket 80 has a tubular member 82 formed from bi-stable cells 83 as discussed above. In addition, the gasket 80 has at least one seal 84 along at least a portion of its length. An example of a seal 84 may include one or more layers internally, externally, or both arranged with respect to tubular member 82. In addition, the layer (s) may be mixed together with openings formed in the cells.

Figure 14 shows an embodiment with an internal and an external seal 84. Figure 15 shows a gasket 80 with only an internal seal. The seal 84 can be formed from an elastomer or other material. Furthermore, the properties of the seal 84 allow it to at least adjust to the expansion value of the tubular member 82. Folds or other design characteristics of the seal 84 can be used to facilitate the expansion.

A resin or catalyst 85 can also be used to allow the seal 84 to set after setting. In an alternative embodiment, a resin or other liquid material is placed between the 20 layers of seals 84 (as in Figure 14). Once the gasket 80 is placed in the well and expanded, the liquid material can harden or otherwise age to improve the sealing characteristics of the gasket 80. In some applications, hardening of the resin or other material requires heating the material with 25 using an auxiliary tool. The packing 80 can be expanded as described herein and can be provided with a number of bi-stable cells. In a usage embodiment, the gasket 80 is deployed on an input tool that includes an expanding tool. The gasket 80 is positioned at the desired location and expanded to seal against the walls of the jacket or other tubular member. Typically, the gasket 80 is connected to a tube or other conduit which is below the 1 0 1 9- 7 k q i W; Figure 21 extends into packing 80 at the bottom of the borehole. The gasket 80 provides a seal in the annular space to prevent or limit longitudinal fluid flow in the well (the usual use of gaskets). The present invention can also act as a well anchor, which includes or excludes seal 84.

Figure 16 shows an alternative embodiment in which the gasket 80 forms a part of a pipe. In the illustrated embodiment, a well conduit 90 (such as a casing) has a portion (marked as the gasket 80) cut out to form the bi-stable cells. The packing portion 80 then has a seal 84 thereon as described above. In Figure 16, a portion of the sealing material 84 is shown as being removed to reveal the bi-stable cells 83 in the underlying tubular member 82. In Figure 17 the packing portion 80 is shown in its expanded position. It should be noted that in conventional applications, the well line 90, which has no bi-stable cells formed therein, does not expand. Thus, an embodiment for attaching the well pipe to the gasket 80 is to form the gasket 80 as an integral part of the well pipe 90 (note that a welded connection resembles this embodiment and is an alternative method of forming the present invention). Other methods include conventional methods of non-integral connection.

In alternative embodiments, the well conduit has a number of bi-stable cell packings 80 formed thereon. In yet another alternative embodiment, a portion or portions 91 of the well conduit in addition to packer portions 80 is formed of bi-stable cells so that these other portions also expand undergone (see Figure 17). The other portions may or may not have a material disposed thereon. The other portion may, for example, have a screen or filter material disposed thereon to provide a sand screen in the well.

Referring to Figures 18A-C, an alternative design of the present invention is shown in a schematic, partially in sectional view. The expandable gasket is shown in the contracted or expanded position and in partial side view (Figure 18C). The gasket shown comprises a tubular base member 82 formed from thin struts 21 and thick struts 22 which, as described above, form bi-stable cells 23/83. Slats 92 are attached to tube 82 at an edge and generally extend longitudinally in the illustrated embodiment (see Figure 18C). More specifically, each slat 92 is attached to the tube 82 at the thick struts 22 and the width of the slats is such that they at least overlap the adjacent slat when the tube 82 is in its expanded position. Although shown to have attached a slat to each of the thick struts, the gasket may have a slat attached to alternating thick struts 22 or in other configurations. Furthermore, the slats can extend in a direction other than the longitudinal direction. The slats 92 slide over each other during expansion such that the outside of the tubular member 82 is covered by the overlapping slats 92.

A seal 84 may be attached to the slats 92 to obtain the seal for the gasket. Although shown as folded in the figures, the seal 84 may have other features that facilitate its ability to expand with the slats 92 and tubular member 82. The seal 84 may also have other aforementioned features (e.g., resin, internal seal, etc.).

It should be noted that although described as a gasket, the present invention can be used to provide long-length insulation as opposed to a conventional gasket or bottom-to-hole tool that generally seals over a relatively short 1ang distance. The present invention can thus be used in a manner similar to a jacket for obtaining insulation over a greater length.

Figure 19 shows a perspective view of gasket 80 (or insulation device) with a number of slats 92 attached thereto in an overlapping arrangement as described above. The tube 82 includes an extension 94 extending at the ends in the longitudinal direction of the cells. Slats 92 can be attached to the end extensions 94 on certain portions of the thick struts 22 and / or on certain thick struts 22. For example, in one embodiment, the struts 92 are attached to the thick struts that are longitudinally aligned with the end extensions 94. Although generally shown as being attached to an end edge of the slats 92, the slats may also be at a location between the edges on the tube 82 are confirmed.

Figure 20 shows an expandable tubular member (or conduit) 90 disposed in a well 100. The conduit 90 includes a plurality of spaced gaskets 80 or expandable sealing devices. The expandable sealing devices 80 engage the well bore wall thereby preventing flow into the annular space. Each annular micro space formed between the expandable tubular member 90 and the well 100 (which may be provided with a casing) is thereby sealed in the longitudinal direction to thereby limit or prevent unwanted flow. The conduit 90 may, if desired, be provided with one or more such gaskets 80 for controlling the flow. Further, the gaskets 80 may be spaced at a regular distance or at any other predetermined distance as needed to control the flow in the annular space.

In an example schematically shown in Figure 21, the individual connections of tubular members 90 are interconnected by a gasket 80 for dividing into compartment each connection of pipe from the adjacent connection (s). The 1019753 24 gasket 80 can be a separate connector, as shown in Figure 21, or it can be formed as part of the connection. Accordingly, the gasket 80 may be disposed at one end of the joint 90, in the center of the joint 90 or at any other location along its length. In one embodiment, both conduit 90 and gaskets 80 of Figures 20 and 21 are formed from bi-stable cells.

Referring generally to Figures 22A-B, an alternative embodiment of the present invention is disclosed. The device shown in these figures can be used as a gasket, suspension member, casing cushion or other device that requires expansion and for ease of description is generally referred to herein as an expandable tubular member 120. The expandable tubular member 120 includes a plurality of cells 122 formed therein, such as laser cutting, jet cutting, water jet cutting, or other manufacturing methods. The cells 122 are oriented such that a plurality of longitudinal struts 24 are formed on the expandable tubular member 120. Thus, as shown in the figures, the longitudinal struts 124 are between longitudinal lengths of cells 122 with the cells 122 having relatively thinner struts 126 extending between adjacent longitudinal struts 124. As shown in the figures, if the adjacent longitudinal struts 124 open longitudinally are moved away from each other (e.g., in opposite directions), the cells 122 to radially expand the structure. Not all longitudinal struts 124 have to move; alternative longitudinal struts 124 can be moved while the other struts remain stationary. The relative movement of the longitudinal struts 124 provides for the expansion of the cells 122 and the expandable tubular member 120. This type of cell is an example of an expandable cell that is not bi-stable.

A locking mechanism 128 can be used to maintain the expanded position of the expandable tubular member 120. As shown in Figures 22A-B, the expandable tubular member 1019753 may be provided with one or more latching mechanisms 128 spaced apart along the length of the expandable tubular member 120 and radially spaced apart about the expandable tubular member 120. An embodiment of the locking mechanism is shown in Figures 23A-B. In the illustrated embodiment, the locking mechanism 128 includes a pawl (or finger) 130 extending from a longitudinal strut 124 and cooperating with a pair of detent teeth 132 disposed on another longitudinal strut 124. The detent teeth 132 extend from a hell The longitudinal brace 124 accommodates the relative movement of the pawl 130 to the pawl teeth 132. The pawl teeth 132 generally permit movement of the pawl 130 thereon in a first with the expansion of the expandable tubular member 120. coherent direction and prevents movement of the pawl 130 in the opposite direction. Once in the expanded position 15, the pawl 130 acts as a locked strut, which prevents contraction of the expandable tubular member 120. To increase the structural integrity of the expanded tubular member 120 and to resist forces that attempt to move the expandable tubular member 120 from an expanded position or position to a reduced position. The expandable tubular member 120 may include a plurality of locking mechanisms 128.

Although shown as a pawl member, as an alternative, the locking mechanism may have fewer individual positions, such as one, in which the pawl locks in the fully extended position. In another embodiment, the pawl may be a resilient finger biased to an extended position snapping into a groove in an adjacent longitudinal strut 124. Similarly, the adjacent struts 124 may each have resilient pawls cooperating about the device. lock the expanded position only if the tubular member 120 has reached the expanded position. These are just a few examples of the many possible alternatives to the locking mechanism 128.

Various other tubular expansion mechanisms and expandable cells may also be used such expandable tubular members and other devices. Details of a type 5 expandable cell are shown, for example, in Figures 24A, 24B, 25A and 25B. In this embodiment, as in other embodiments, the cell is transferred from a compressed state to an expanded state.

During movement from the compressed position to an expanded position and depending on the environmental conditions as well as on the materials used, material thickness and other design parameters of the cell and devices formed from the cell, some areas of the cell and braces may experience plastic deformation. 24A, 24B, 25A and 25B show alternative embodiments of a cell in compressed and expanded positions. In these embodiments, one of the struts 21 (shown as the thinner upper strut) has thinned portions 140 that serve as flexible hinges or connections. The diluted portions 140 are preferably placed in areas where plastic deformation of the strut is likely to occur if the strut moves from a compressed to an expanded position. For example, the diluted portions 140 may be located near the intersection of the struts 21, 22 to provide an area less susceptible to plastic deformation. Although the figures show a number of diluted portions 140, the strut may be provided with a single diluted portion 140, for example, at an area of increased plastic deformation. The diluted portions 140 can also be placed in other positions along the struts 21, 22 for other purposes. The diluted regions 140 define couplings 142 therebetween, which include portions that are generally thicker than the diluted portions 140. Placing a plurality of diluted portions 140 along the length of a strut 21, 22 produces a plurality of connections 142.

1019753 27

Another factor in determining the arrangement of the diluted portions 140 is the number, placement, and design of the connections. Although shown in the figures as having a uniform thickness, the joints 142 may also have a variation in thickness 5 for further adjusting the expansion, contraction, and other characteristics of the cell as desired. In a broad aspect of the inventions, therefore, at least one of the struts 21, 22 has a thickness which varies. Other factors can also be considered in the placement of the diluted portions 140 and the thickness variations of the struts 21, 22. The diluted portions may also be present at the intersection of the struts 21, 22.

Figures 24A and 24B show a cell with three connections and figures 25A and 25B show a cell with two connections. Although Figures 24A-25B only disclose a single cell, the cell can be included in a tool, such as a tube, with a plurality of cells such as those shown in Figures 4A and 4B. The figures show a single cell to more clearly show the basic concept and the cell design. The handles shown in the figures are not part of the cell structure but are only used with test cells to facilitate testing of the cells.

Referring generally to Figures 26A and 26B, another embodiment of expandable cells, referred to as expandable cells 150, is shown. Each expandable cell 150 comprises a thick strut 152 and one or more thin struts 154, for example two thin struts 154. In the illustrated embodiment, each expandable cell 150 comprises a pair of thin struts, and each thin strut 154 has a pair hinged with respective adjacent thick ends coupled ends 156. Each end 156 can be provided with pins which are hingedly received in corresponding openings 158.

If the number of expandable cells 150 from the figure

26A to the expanded position shown in Figure 26B

1019753 28 is moved to deform thin struts 154 sufficient to allow pivoting of pins 156 into their corresponding openings 158. As best shown in Figure 26B, the pair of thin struts 154 forming each cell 150 has outer ends 156 hingedly connected to upper attachment regions 160 of the lower thick strut 152. The opposite ends of each pair of thin struts 154 are pivotally coupled to a lower attachment region 162 of the next upwardly thick thick strut 152. It should be noted that placement expressions such as upper and lower are used only to facilitate explanation of the placement of various features with respect to the figures and not be interpreted as limiting.

In another embodiment shown in Figs. 27A and 27B, a number of expandable cells, designated by reference numeral 164, are each provided with a thick strut 166 and one or more thin struts 168. Each thick strut 166 is generally curved and with a corresponding thin strut 168 connected to a fixed connection area 170, which is arranged at a generally central location along the outer or convex portion of the curved thick brace. The outer ends of each thin strut 168 are hingedly coupled to the next adjacent thick strut 166 via a hinge joint 172, which may include a ball and sleeve.

As the plurality of cells are moved from the position contracted in Figure 27A to the expanded position shown in Figure 27B, thin struts 168 bend or deform as their outer ends pivot at each hinge joint 172. As with many of the other cells described herein, if the thin one tries

When the braces 168 move beyond their point of greatest deflection, the stored spring energy urges the cells 164 to their stable expanded position shown in FIG. 27B. As with the ones in Figures 26A and 26B

bi-stable cells shown thus move cells 164 between a stable contracted state and a stable expanded state.

Another embodiment of an expandable cell is shown in Figures 28A and 28B. In this embodiment, each expandable cell 174 is formed from a thick strut 176 and a thin strut 178. Each thin strut 178 has a pair of ends 180 pivotally coupled to a thick strut. For example, a given thick brace may be provided with a pair of apertures 182 for pivotally receiving pin or ball-shaped ends 180. Additionally, thin brace 178 is fixedly coupled in an alternating pattern to adjacent thick braces 176. Each cell in the illustrated embodiment comprises for example three fixed couplings 184, which alternate between adjacent thick struts 176. With this design, the expandable cells 174 are movable again between a stable contracted position, as shown in Figure 28A, and a stable expanded position, as shown in Figure 28B.

Referring to Figures 29A and 29B, another design of an expandable cell is shown. In this embodiment, each of a plurality of expandable cells 186 includes a thick strut 188 and at least a pair of stacked thin struts 190 and 192, respectively. Thin struts 190, 192 are generally arranged in a stacked orientation and connected by a connector 194. Thin strut 192 comprises a pair of ends 196 attached to a corresponding thick strut 188. An intermediate connecting region 198 of thin strut 192 is attached to the next adjacent thick strut 188, as best shown in Figure 29B. Thin strut 190, on the other hand, has unattached ends 200. Stops 200 are enclosed in an adjacent engagement with a notched area 202 formed in the same thick strut 188 to which ends 196 are attached. As the number of expandable cells 186 is moved from the contracted position shown in Figure 29A to the expanded position shown in Figure 29B, each pair of thin struts 190 and 192 deforms to a deflection point where stored energy in 1019753 is the maximum of the thin struts. If the thin braces are moved past this deflection point, the stored energy is released to facilitate expansion of the cells to their expanded position.

Of course, with many of these types of bi-stable cells, the extent of expansion can be limited by an external limitation. For example, if the bi-stable cells are used to form a tubular member, the tubular member can be expanded against the wall of a well bore which prevents the cells from moving to their fully expanded position. Usually, the size of the tubular member is chosen to allow expansion of the cell at least beyond the point of maximum distortion. Depending on the material used, the cells can in fact cooperate to apply an outward radial force against the wall of the well bore.

Referring generally to Figures 30A and 30B, another design of an expandable cell is shown. Each expandable cell 204 includes a pair of curved thin struts 206 pivotally coupled to a corresponding thick strut 208 at a generally centralized running area 210 via hinge ends 212. Generally opposite hinge ends 212, thin struts 206 include outer hinge ends 214, pivotally coupled be with the following adjacent thick brace 208. Hinge ends 212 and 214 can be formed in a number of configurations, such as ball joints, pin joints, etc. Removal of each thin brace 206 is prevented by ligaments arranged appropriately at hinge ends 212 and 214, respectively. The ligaments 216 and 218 are coupled between the thin strut 206 and the corresponding thick struts 208.

31A-31C shows another type of expandable cell 220. In this embodiment, a thick strut 222 is coupled to an even more thin strut 224 by one or more spring elements 226. In the particular embodiment shown, two spring elements 226 1019753 are generally formed in the form of a horn, with the base of each horn connected to thick strut 222 and the tip of each horn coupled to the adjacent thin strut 224. In this embodiment, a thin strut 224 is connected by a flexible hinge 228 to each spring element 226. The two thin struts 224 are coupled to each other by a central beam 230 and a pair of flexible hinges 232.

When cells 220 are expanded from a contracted position shown in Figure 31A to an expanded position shown in Figure 31C, spring elements 226 flex outward and store spring energy. With this design, thin struts 224 usually do not undergo significant distortion during movement from the contracted position to the expanded position. Rather, spring elements 226 are elastically deformed if they are forced outward during movement of central beam 230 from the contracted position to the expanded position. If spring elements 226 are bent outwards, they store spring energy at least to the point of maximum bend shown in Figure 31B where thin struts 224 are generally parallel to thick strut 222. Once central beam 230 moves past this point of maximum stored spring energy, spring elements 226 tend to release stored energy and move inwardly thereby urging thin struts 224 and central beam 230 to the expanded position best shown in Figure 31C. Deformation of hinges 228 and 232 facilitates the pivoting of thin struts 224 from the contracted position to the expanded position.

A double horn cell design is shown in Figures 32A and 32B. In this design, a plurality of thick struts 236 are coupled together via thin struts 238 and horn spring members 240. More particularly, each thin strut 238 is coupled to two horn spring members 240 to allow storage of a larger amount of energy. This larger energy storage provides additional positive energy for opening cells 234 to their expanded positions such as 1019753 32 shown in Figure 32B.

In the illustrated example, each double horn cell 234 has two outer horn spring members 240 coupled to a thick strut 236, and two inner horn spring members 240 coupled to the next adjacent thick strut 236. A thin strut 238 is coupled to each cooperating pair of inner and outer horn spring members via appropriate hinge regions 242. If the double horn cells 234 are moved from the contracted position shown in Figure 32A to the expanded position shown in Figure 32B, the cooperating pairs of inner and outer horn spring members 240 bent outward to a point where the thin struts 238 are generally aligned. Following this point of expansion, the horn spring members 240 begin to release the stored spring energy and force thin braces 238 to the fully expanded position.

Other forms of spring elements can also be used in facilitating expansion of a number of cell types. For example, FIG. 33 shows an expandable cell 244 in which adjacent thick struts 246 are coupled by a different type of spring members 250 to a thin strut 248. Spring struts 250 may be wound, corrugated, or along other webs that obstruct the transition of thin strut 248 from the contracted position shown in Figure 33 to an expanded position.

Another type of spring system is shown in Figure 34 as an expandable cell 252. A pair of thick struts 254 is coupled by a pair of wavy thin struts 256. The design of thin struts 256 includes a number of spring elements 258, which include both bending of the thin struts 256 and expansion of the cell 252 by storing and then releasing spring energy. The spring energy is released as the transition from thin struts beyond a point of maximum bending to a fully expanded position.

To lock the entire device, e.g. tubular member, in the expanded position in 1019758 33, a locking mechanism can be used to prevent the individual cells from contracting. Examples of locking mechanisms may be associated with individual cells or they may be arranged at one or more locations along the expandable device. 35A-35D shows a type of locking mechanism 258. In this embodiment, a post 260 is slidably received in a corresponding recess 262. A ratchet finger 264 generally extends transversely to the post 260. More specifically, ratchet finger 264 includes an engagement end 266 located in a recessed area 268 of post 260 when the entire device and locking mechanism 258 are in a contracted position as shown in Figure 35A.

When the device, e.g. tubular member, is expanded, ratchet finger 264 is deflected away from an adjacent support surface 270, as best shown in Figure 35D. The ratchet finger 264 continues to slide along the side of post 260 if the device is expanded to a maximum size shown in Figure 35C. If the expansion force is released, any substantial movement from post 260 to the contracted position is blocked by ratchet finger 64, as shown in Figure 35D. As style 260 attempts to move to its contracted position, engagement end 260 is firmly pressed into its intervening engagement with the side of style 260. Additionally, support surface 270 limits the movement of ratchet finger 264 in the contracting direction. The side wall of pillar 260 can be provided with teeth or other intervening features, which help prevent movement of pillar 260 back to the contracted position.

Another example of a locking mechanism 272 is shown in Figures 36A-36D. In this embodiment, a fork pawl 274 is formed in the expandable device, such as in the shore of an expandable tubular member. Fork retainer 274 includes a pair of teeth 276, each of which has a diverging end 278. In the contracted position, 1019753 34 teeth 276 are received in an opening 280, which generally has the shape of an hourglass. In other words, diverging ends 278 are located in a diverging or expanded portion 282 of the opening 280 and must be moved through a narrow or narrowed portion 284 when the device is expanded.

During expansion of the tubular member or other device, diverging portions 282 are pulled through narrowed area 284 (see Figures 36B and 36C).

Once teeth 276 have been pulled free from opening 280, the diverging portions 282 spring out again to their normal position. In this position, diverging portions 282 are wider than the entrance to opening 280 and fork pawl 274 is prevented from re-entering the opening 280. The entire device is thus held in its expanded position.

Another example of a locking mechanism 284 is shown in Figure 37. Locking mechanism 284 is designed for use with horn-style cells. In the specific example shown, a slot 286 is formed between a pair of resilient horn members 288 within a thick strut 290 of an expandable cell 292. A wedge 294 extends from an adjacent thick strut 296 into slot 286. If cell 292 is expanded wedge 294 pulled out through slot 286. The size of the wedge point 298 and slot outlet 300 are selected to intervene when cell 292 is in an expanded position. This prevents bending of horns 288 to slot 286 and thereby prevents collapse of the expanded cell.

Referring generally to Figures 38A and 41B, a number of combinations of expandable cell and locking mechanisms are shown. With specific reference to Figs. 38A and 38B, an embodiment of an expandable cell 302 includes thick struts 304 coupled to one another by thin struts 306 via spring members 308. Each thick strut 304 includes one or more, for example, two ratchet fingers 310 passing along 1019753 35 a corresponding pawl surface 312 formed correspondingly on expanded areas of the thin struts (see FIG. 38B).

Ratchet surface 312 may be provided with ratchet teeth engaging the end of a corresponding ratchet finger 310. If the expandable cell 302 is transferred from its contracted position as shown in Fig. 38A to an expanded position, as shown in Fig. 38B, ratchet fingers 310 bent away from a support surface 314 during sliding along corresponding ratchet surfaces 312. The ends of the ratchet fingers 310 do not allow sliding movement of corresponding ratchet surfaces 312 back to the contracted position. Furthermore, support surfaces 314 can be relied upon to limit any bending of fingers 310 back to the contracted position. Thus, when the expandable cell is in its expanded position, each of the pawl fingers 310 acts against a corresponding pawl surface 312 to support the cell against collapse.

Another embodiment of the system is shown in Fig. 39 and uses fingers in the form of pawl latch 316. In this embodiment, each pawl latch is formed in a suitable thick strut 304 by creating an open area 318, which 20 is formed to receive a corresponding portion 320 of thin strut 306 when in the contracted position. Each retainer link 306 may be provided with a plurality of teeth 322 arranged to engage corresponding teeth 324 extending from portion 320. Additionally, a relief cut 326 may be formed along retainer link 316 generally opposite open area 318. Relief cut 326 allows pawl latch 316 to flex if teeth 322 are pulled past teeth 324 during transition of the cell from a contracted position to an expanded position. Teeth 322 and 324 are designed to prevent cell closure when expansion begins. The pawl latch 316 thus effectively moves along section 320 while retaining the cell with any additional degree of expansion. As an alternative to teeth 1019753 36, the latch 316 and cooperating portion 320 may use other types of intervening features to prevent cell contraction.

The locking mechanisms can also be used in conjunction with expandable sets, which are not necessarily bi-stable cells. For example, in Figure 40A, an expandable cell 330 includes a thin strut 322 disposed in an expandable "foreleg" shape between the thick struts 344 to which it is connected. A locking mechanism 336 cooperates with one or more of the expandable thin struts 332 to hold the expandable sets 333 at an expanded position. As shown in Fig. 40B, a locking mechanism 336 can be combined with any expandable cell 330 or there can be several expandable cells for each locking mechanism 336.

In this embodiment, locking mechanism 336 includes a post 338 that has external teeth 340. Pillar 338 is slidably received in an aperture 342 that is defined by one or more flexible fingers 344 that have engagement points 346 that engage teeth 340. Fingers 344 flex outward to allow teeth 340 to slide past engagement points 346 if the cell is expanded, but engagement points 346 prevent post 338 from moving in a direction toward the contracted position. Thus, once expandable cell 330 is expanded, locking mechanism 336 prevents cell contraction.

A similar design is shown in Figures 41A and 41B. This design combines the expandable cell described with reference to Figure 40A and a locking mechanism of the type described in Figures 36A-36D. Thus, if the number of expandable cells 330 is moved from the position contracted in Fig. 41A to the expanded position shown in Fig. 41B, the thin brace of the wishbone style is expanded. Simultaneously, teeth 276 are pulled from their corresponding aperture 280 to a position which prevents return of fork 274 into the aperture 280. The locking mechanism may be designed such that teeth 276 are withdrawn from and blocked against re-entry of opening 280. Alternatively, teeth 276 may be designed for intervention with corresponding teeth or other intervening features 350 disposed along the outer boundary of each opening 280 to return movement of teeth 276 in opening 280.

It should also be noted that expandable devices, such as expandable tubular members, may be formed with a variety of cells and locking mechanisms, which have different shapes, as changes in size or type, as shown schematically in Figure 42. By stacking cells of different length or eccentric displacement in plate or tube, it is possible, for example, to design an opening bias in the structure. The expandable device may be designed to allow certain rows of cells to open prior to other rows of cells or that the cells open in a predetermined pattern or with a predetermined value. For example, in Figure 42, an expandable device 352 comprises rows of 20 expandable cells 354. However, different rows 354 have cells of different lengths, for example cells 356, 358 and 360. This allows certain rows of cells to open prior to adjacent rows of cells because , at least with certain cell designs, the length of the cell influences the force required to expand the cell. Inclusion of 25 different rows of cells in an expandable device allows the user to know the extent of expansion for a given deployment force and facilitates the design of devices that have cells that open in a predetermined order. In addition, the use of different types of cells can improve compliance of the expandable device 30 if the deployment force is not uniform along the length of the device.

1019753 38

It will be understood that the above description is of exemplary embodiments of the present invention and that the invention is not limited to the specific forms shown. The expandable cells can be combined, for example, in a number of tubular members and other expandable structures; the size and shape of the expandable cells and locking mechanisms can be adjusted. The material types used can be changed depending on the specific application; and a variety of mechanisms can be used to expand the cells. The different cells can also be formed by a variety of techniques including laser cutting, jet cutting, water jet cutting and other forming techniques. These and other modifications can be made to the design and arrangement of the elements without departing from the spirit of the invention as expressed in the appended claims.

1019753

Claims (5)

1. Expandable device provided with an expansion member with a number of cells which can be expanded from a closed position to an open position, wherein each cell has a thin brace hinged to a thick brace with a pivot connection. The expandable device of claim 1 wherein the thin brace and thick brace of each cell are pivotally coupled through a pin connection. The expandable device of claim 1 wherein the thin brace and thick brace of each cell are pivotally coupled through a ball and bush connection. The expandable device of claim 1 wherein the thin strut is coupled between a fixed end and a pivotable end. The expandable device of claim 1 wherein the expandable member is a tubular member that undergoes radial expansion during cellular expansion.